Double diaphragm pumps alternately pressurize and exhaust two opposing motive fluid chambers to deliver pumped media during each stroke of the pump. For example, the motive fluid chambers may be pressurized with compressed air delivered by an air motor. Each motive fluid chamber is in contact with a flexible diaphragm that separates the motive fluid chamber from a pumped media chamber. The pressurized motive fluid drives the flexible diaphragms, and the diaphragms pump the fluid media through the pumped media chambers. Typical diaphragms may include a flexible disc mounted between rigid diaphragm plates, fixed with a bolt through the diaphragm plates that attaches to a connecting shaft. The diaphragm plates, bolts, and other areas on the pumped media side of the diaphragm may allow pumped media to collect and stagnate, and in certain circumstances may allow for microorganism growth and/or recirculation of older pumped media and/or residue.